Rare high-end 'speakers from Victor's "Select" series which also included the P-L10 and M-L10 pre/power combo, QL-A75 turntable, MC-L1 and MC-L10 cartridges.
The "L" naturally, and previsibly, stands for Laboratory - the US prefered the Select thing.
The Zero-10 was a Zero-1000 in Japan : same loudspeaker, just two more zeroes.
Blue baffle apart, something which Technics and Pioneer also went for at about the same time, the Zero-10 is less conventional than it may seem but it does conceal its key features very well indeed.
If dressed in wood, the enclosure does in fact hold a frame made of inert composite material designed with the aid of a "modal analysis" computer program ; its "super-elliptical" shape helps prevent enclosure disformation and standing waves.
The drivers aren't white just to look classy or have a slight Yamaha flavor : they are in fact coated with fine ceramics by way of "Physical Vapor Deposition" and "Plasma Blast" processes.
The woofer is secured from both front and back sides of the enclosure ; the super tweeter is a highly efficient and horn-loaded Dyna-Flat ribbon, allowing frequency response up to... 100Khz !
Nothing really ground-breaking, no revolution, just a careful blending of high-end elements which Victor (JVC outside Japan) would carry over, ever refining the blend, to acclaimed and cost-no-object units such as the Zero L1000, SX-900 and later Spirit SX-1000 variants.
The Zero-10 however doesn't seem to have sold too well, unlike its select P-L10 and M-L10 companions which sold like hotcakes and were kept available in Japan until the very late 1980s.
Select was fine, Laboratory was fine... maybe the blue front wasn't ?
A real pair here.